Excel Column Number

Problem

Convert an Excel column title such as A, Z, AA or ZY to its 1-based column number.

Process characters left to right treating the title as a base-26 number where A is 1 rather than 0: result = result * 26 + (letter position). Assume s contains only uppercase letters.

Hint

Shift the running value by one base-26 digit per character, with A having value 1.

Test cases

case 1

in: ["A"]

expected: 1

case 2

in: ["Z"]

expected: 26

case 3

in: ["AA"]

expected: 27

case 4

in: ["ZY"]

expected: 701

case 5

in: ["AZ"]

expected: 52

Starter codePython

def excel_column_number(s):
    # Your code here
    pass

5 test cases · run your code against them in the editor